<!--
  $Id: serverview.html,v 1.8 2012-07-17 08:22:19 gaudenz Exp $
  Copyright (c) 2006-2010, JGraph Ltd
  
  Server-View example for mxGraph. This example demonstrates using
  a server-side image of the graph as the diagram in the client. This
  may be used to improve drawing-speed in older browser and on devices
  with slower processors.
-->
<html>
<head>
	<title>mxGraph using Server-side Image</title>

	<!-- Sets the basepath for the library if not in same directory -->
	<script type="text/javascript">
		mxBasePath = '/mxgraph/javascript/src';
	</script>

	<!-- Loads and initializes the library -->
	<script type="text/javascript" src="/mxgraph/javascript/src/js/mxClient.js"></script>

	<!-- Overrides certain methods required for the server-side-image to be used. -->
	<script type="text/javascript">
		// Makes the background of the in-place editor non-transparent
		var previousStartEditing = mxCellEditor.prototype.startEditing;
		mxCellEditor.prototype.startEditing = function (cell, trigger)
		{
			previousStartEditing.apply(this, arguments);
	
			var state = this.graph.getView().getState(cell);
	
			if (state != null)
			{
				var color = mxUtils.getValue(state.style, mxConstants.STYLE_FILLCOLOR, 'white');
				this.textarea.style.background = color;
			}
		};
	
		// Replaces the event firing mechanism in the graph view since there are
		// no longer any DOM elements that fire events for the actual states we
		// have to find the state under the mouse using graph.getCellAt and then
		// fire the event for the state from here instead.
		// FIXME: Since we do not render the label we don't have the label bounds
		// here which means hit detection will only work for the vertex bounds,
		// the edge but not for overlapping labels or most part of the edge labels.
		mxGraphView.prototype.installListeners = function()
		{
			var graph = this.graph;
			var container = graph.container;
			
			if (container != null)
			{
				var md = (mxClient.IS_TOUCH) ? 'touchstart' : 'mousedown';
				var mm = (mxClient.IS_TOUCH) ? 'touchmove' : 'mousemove';
				var mu = (mxClient.IS_TOUCH) ? 'touchend' : 'mouseup';
				
				// Adds basic listeners for graph event dispatching
				mxEvent.addListener(container, md,
					mxUtils.bind(this, function(evt)
					{
						var pt = mxUtils.convertPoint(graph.container,
							mxEvent.getClientX(evt), mxEvent.getClientY(evt));
						var cell = graph.getCellAt(pt.x, pt.y);
						var state = this.getState(cell);

						if (state != null)
						{
							graph.fireMouseEvent(mxEvent.MOUSE_DOWN,
									new mxMouseEvent(evt, state));
						}
						// Condition to avoid scrollbar events starting a rubberband
						// selection
						else if (this.isContainerEvent(evt) &&
							((!mxClient.IS_IE && 
							!mxClient.IS_GC && !mxClient.IS_OP && !mxClient.IS_SF) ||
							!this.isScrollEvent(evt)))
						{
							graph.fireMouseEvent(mxEvent.MOUSE_DOWN,
								new mxMouseEvent(evt));
						}
					})
				);
				mxEvent.addListener(container, mm,
					mxUtils.bind(this, function(evt)
					{
						var pt = mxUtils.convertPoint(graph.container,
							mxEvent.getClientX(evt), mxEvent.getClientY(evt));
						var cell = graph.getCellAt(pt.x, pt.y);
						var state = this.getState(cell);
	
						if (state != null)
						{
							graph.fireMouseEvent(mxEvent.MOUSE_MOVE,
									new mxMouseEvent(evt, state));
						}
						else if (this.isContainerEvent(evt))
						{
							graph.fireMouseEvent(mxEvent.MOUSE_MOVE,
								new mxMouseEvent(evt));
						}
					})
				);
				mxEvent.addListener(container, mu,
					mxUtils.bind(this, function(evt)
					{
						var pt = mxUtils.convertPoint(graph.container,
							mxEvent.getClientX(evt), mxEvent.getClientY(evt));
						var cell = graph.getCellAt(pt.x, pt.y);
						var state = this.getState(cell);
	
						if (state != null)
						{
							graph.fireMouseEvent(mxEvent.MOUSE_UP,
									new mxMouseEvent(evt, state));
						}
						else if (this.isContainerEvent(evt))
						{
							graph.fireMouseEvent(mxEvent.MOUSE_UP,
								new mxMouseEvent(evt));
						}
					})
				);
				
				// Adds listener for double click handling on background
				mxEvent.addListener(container, 'dblclick',
					mxUtils.bind(this, function(evt)
					{
						var pt = mxUtils.convertPoint(graph.container,
							mxEvent.getClientX(evt), mxEvent.getClientY(evt));
						var cell = graph.getCellAt(pt.x, pt.y);
						
						graph.dblClick(evt, cell);
					})
				);
							
				// Adds basic listeners for graph event dispatching outside of the
				// container and finishing the handling of a single gesture
				mxEvent.addListener(document, md,
					mxUtils.bind(this, function(evt)
					{
						if (this.isContainerEvent(evt))
						{
							graph.panningHandler.hideMenu();
						}
					})
				);
				mxEvent.addListener(document, mm,
					mxUtils.bind(this, function(evt)
					{
						// Hides the tooltip if mouse is outside container
						if (graph.tooltipHandler != null &&
							graph.tooltipHandler.isHideOnHover())
						{
							graph.tooltipHandler.hide();
						}
						
						if (this.captureDocumentGesture &&
							graph.isMouseDown &&
							!mxEvent.isConsumed(evt))
						{
							graph.fireMouseEvent(mxEvent.MOUSE_MOVE,
								new mxMouseEvent(evt));
						}
					})
				);
				mxEvent.addListener(document, mu,
					mxUtils.bind(this, function(evt)
					{
						if (this.captureDocumentGesture)
						{
							graph.fireMouseEvent(mxEvent.MOUSE_UP,
								new mxMouseEvent(evt));
						}
					})
				);
			}
		};
	</script>

	<!-- Example code -->
	<script type="text/javascript">
		// Program starts here. Creates a sample graph in the
		// DOM node with the specified ID. This function is invoked
		// from the onLoad event handler of the document (see below).
		function main(container)
		{
			// Checks if the browser is supported
			if (!mxClient.isBrowserSupported())
			{
				// Displays an error message if the browser is not supported.
				mxUtils.error('Browser is not supported!', 200, false);
			}
			else
			{
				// Creates the graph inside the given container
				var graph = new mxGraph(container);

				// Holds the current image
				var img = null;
				var loader = new Image();
				loader.src = 'images/loading.gif';
				loader.style.zIndex = 1;
				loader.style.visibility = 'hidden';
				loader.style.position = 'absolute';
				
				graph.container.insertBefore(loader, graph.container.firstChild);
				
				// Disables the DOM-based rendering in the graph and updates the
				// display image on each validation step using the Export servlet
				// on the graph
				graph.view.rendering = false;
				
				// Installs a post-validation repaint of the complete graph
				graph.view.validate = function()
				{
					loader.style.left = graph.container.scrollLeft + graph.container.clientWidth / 2 - 32;
					loader.style.top = graph.container.scrollTop + graph.container.clientHeight / 2 - 32;
					loader.style.visibility = 'visible';
					mxGraphView.prototype.validate.apply(this, arguments);

					var t0 = new Date().getTime();
					var bounds = graph.getGraphBounds();

					// Note that we send out an XML version of the view which
					// allows us to keep most customizations on the client-side.
					// No deltas are used here, the complete view is sent to the
					// server on each update.
					var node = mxUtils.getViewXml(graph, 1);
					var xml = encodeURIComponent(mxUtils.getXml(node));

					var onload = function(req)
					{
						var dt = (new Date().getTime() - t0) / 1000;
						//mxLog.debug('post returned after '+dt+' secs');
					
						if (req.getStatus() == 200)
						{
							var image =new Image();

							// Disable DnD events on images in IE. FIXME: Rubberband
							// events are ignored in IE when starting on the image.
							if (mxClient.IS_IE)
							{
								graph.view.isContainerEvent = function(evt)
								{
									var source = mxEvent.getSource(evt);
					
									return (source == image ||
										source == this.graph.container ||
										source.parentNode == this.backgroundPane ||
										(source.parentNode != null &&
										source.parentNode.parentNode == this.backgroundPane) ||
										source == this.canvas.parentNode ||
										source == this.canvas ||
										source == this.backgroundPane ||
										source == this.drawPane ||
										source == this.overlayPane);
								};
							}
							
							// Less flickering if the old image is removed after
							// the new image was received from the server
							image.onload = function()
							{
								if (img != null)
								{
									img.parentNode.removeChild(img);
								}
						
								img = image;
								graph.container.insertBefore(img, graph.container.firstChild);
								loader.style.visibility = 'hidden';
								
								var dt = (new Date().getTime() - t0) / 1000;
								//mxLog.debug('received '+img.clientWidth+'x'+img.clientHeight+' pixels in '+dt+' secs');
								graph.setEnabled(true);
							};

							// URL contains timestamp to avoid caching in the browser
							image.src = '/ServerView?'+new Date().getTime();
							image.style.position = 'absolute';
							image.style.left = bounds.x - 4;
							image.style.top = bounds.y - 4;
							image.style.zIndex = -1;
						}
					};

					var onerror = function(req)
					{
						//mxLog.debug('error: '+req.getStatus());
					}
					
					//mxLog.debug('sent '+(xml.length/1024)+' KB');
					graph.setEnabled(false);
					new mxXmlRequest('/ServerView', 'xml='+xml).send(onload, onerror);
				};

				// Uncomment the following if you want the container
				// to fit the size of the graph
				//graph.setResizeContainer(true);
				
				// Enables rubberband selection
				new mxRubberband(graph);
				graph.setConnectable(true);
				graph.setPanning(true);
				graph.setTooltips(true);
				
				// Gets the default parent for inserting new cells. This
				// is normally the first child of the root (ie. layer 0).
				var parent = graph.getDefaultParent();
				//mxLog.show();

				// Adds cells to the model in a single step
				graph.getModel().beginUpdate();
				try
				{
					var v1 = graph.insertVertex(parent, null, 'Hello,', 20, 20, 80, 30);
					var v2 = graph.insertVertex(parent, null, 'World!', 200, 150, 80, 30);
					var e1 = graph.insertEdge(parent, null, '', v1, v2);
				}
				finally
				{
					// Updates the display
					graph.getModel().endUpdate();
				}
			}
		};
	</script>
</head>

<!-- Page passes the container for the graph to the program -->
<body onload="main(document.getElementById('graphContainer'))">
<!-- Creates a container for the graph with a grid wallpaper -->
<div id="graphContainer"
	style="overflow:auto;width:500px;height:500px;border: black solid 1px;cursor:default;">
</div>
<br>
<strong>Important:</strong>
<p>
  To use this example, start com.mxgraph.examples.web.main in Java
  and point your<br>browser to:
  <a href="http://localhost:8080/mxgraph/javascript/examples/serverview.html">http://localhost:8080/mxgraph/javascript/examples/serverview.html</a>
</p>
</body>
</html>
